This invention relates to material removing devices and more particularly to a dental model trimmer.
In the course of the preparation of a dental model or workpiece, various finishing operations are required to properly complete the model. For example, the model must be ground, finished, and polished. While some of these operations are frequently carried out by hand, dental model trimmers have become available for automated work on such models. By utilizing various types of abrading surfaces, the apparatus can be utilized for abrading, finishing, polishing, grinding, lapping, etc.
One such dental model trimmer is described in U.S. Pat. Nos. 3,481,086 and 3,603,040. In these patents, a housing is provided in which there is contained a grinding wheel driven by a drive motor. An access opening in the front of the housing exposes a portion of the grinding wheel. A work table is positioned in front of the access opening on which the workpiece can be placed during operation of the grinding wheel. The apparatus is supported in a sediment tray and fluid enters the housing and is removed through the sediment tray.
While such dental model trimmer is useful for working on dental models, the apparatus itself is inconvenient to use and prevents efficient operation and manipulation of the workpiece.
For example, it is frequently necessary to change the abrasive surfaced material when it is used up during the course of regular usage. Additionally, even when operating on a single workpiece, it may be necessary to provide different types of abrasive surfaces, as for example different grades of abrasive material or different kinds of abrasive surfaces for grinding, polishing, finishing, etc. Unless an easily provided means is available for quick replacement of the abrasive surface, numerous apparatus must be provided where such replacement in prior art trimmers usually takes twenty to thirty minutes by skilled persons. This becomes costly, and additional trimmers require excessive space.
Additionally, in manipulating the workpiece, the access opening becomes a limiting factor to the efficient use of the apparatus, where the arrangements of prior art devices do not allow the opening to be positioned very close to the abrading surface. By making the access opening excessively large, safety hazards occur, and when the access opening is too small, it becomes difficult to appropriately manipulate the workpiece against the abrading surface. An additional problem concerns the efficient use of the water spray on the abrading surface.